Ray,
Sounds like your 50A auto-reset breaker is getting tired. Common problem, and your symptoms sound like that. The auto-reset is on the bulkhead in the front basement between the hydraulic pump and battery. Get a replacement from an RV dealer (about $5), disconnect the battery, pull the little red cover off the breaker, and install the new one. Takes about 10 minutes. Voila! Slides come in just fine w/no starting and stopping!! Good luck.
Saw that Cabela's also sells them for $8.
http://www.cabelas.com/spodw-1/0001110.shtml